1. Field of the Invention
The present invention relates to near field analysis apparatuses and, more particularly, to an improvement in the operability thereof.
2. Prior Art
In the related art, various types of near field analysis apparatuses are used to analyze objects smaller than the wavelength of light (for example, see Japanese Unexamined Patent Application Publication No. Hei-11-101743).
In such a near field analysis apparatus, for example, a minute sample to be measured is placed on a flat substrate. When excitation light is incident from a light source at an angle that causes total reflection from the rear surface of the substrate, the propagating light is completely reflected, however, a surface wave known as near field light is generated close to the front surface of the substrate and the sample. This surface wave is localized around the surface of the sample within a region whose size is equal to or smaller than the wavelength of the light.
Thus, in the near field analysis apparatus, when a near field probe having a sharp tip is inserted into the field of this near field light, the near field light is scattered. Part of the scattered light enters the near field probe, is guided to a detector, and is subjected to data processing. The near field analysis apparatus can thus determine the distance between the tip of the near field probe and the sample.
Therefore, by scanning the surface of the sample to be measured while controlling the distance in the vertical direction between the tip of the near field probe and the sample so that the intensity of the scattered light remains constant, it is possible to accurately determine the surface profile of the sample without making contact with the sample.
Furthermore, in this near field analysis apparatus, the tip of the near field probe is only placed in the field of the near field light and does not make contact with the object under measurement. Therefore, the near field analysis apparatus can observe an object smaller than the wavelength of light in a non-contact manner.
In such a near field analysis apparatus, there is still some scope for improvement in terms of the operability. However, in the related art, there is no known suitable technology that is capable of achieving this.